Method of refurbishing a quartz glass component

ABSTRACT

A method is provided of refurbishing a quartz glass component which has been contaminated and eroded due to continuous use in a plasma process apparatus for semiconductor manufacturing. In the method, a surface deposit on the quartz glass component is removed by an appropriate cleaning method which is determined depending on the contamination status, and presence or absence of residual deposit on the cleaned component is carefully inspected through irradiating with light of a predetermined wavelength to cause fluorescence effect. Then the eroded portion of the quartz glass component is restored to the original state by flame treatment and precision machining. As a result, the refurbishment method can increase the mechanical strength of the quartz glass component, enhance the productivity and yield ratio through efficient use of the remaining materials of the quartz glass.

BACKGROUND OF THE INVENTION

The present invention relates to a method of refurbishing a quartz glasscomponent, in which the state of an attachment film of by-products(hereinafter called the “deposit”), erosion and deterioration of aquartz glass component that has been spent by using in a certain processof semiconductor manufacturing, for example, is carefully checked beforecleaning the quartz glass component, an appropriate cleaning method isdetermined depending on the contamination status, the quartz glasscomponent is cleaned with minimum damage to a base material, theresidual deposit is precisely checked to thereby carefully select thequartz glass component and carry out refurbishment rationally. As aresult, the refurbishment method can increase the mechanical strength ofthe quartz glass component which is made of brittle material, preventbreakage arising from growth of thermal stress and strain during a flametreatment in a refurbishment process, enhance the productivity and theyield ratio through efficient use of quartz glass materials, stabilizethe quality and rationalize the refurbishment.

In a plasma processing apparatus for manufacturing a semiconductor orliquid-crystal device, the surface of the quartz glass component iseroded and deteriorated by continuous use in a plasma environment thatcontains fluorine or chlorine-based gas. Even though the quartz glasscomponent is regularly discarded after the predetermined amount oferosion, it is so expensive that improvement of the situation has beendesired.

Due to such demand, various methods have been proposed to remove andrefurbish the eroded and deteriorated portion of the quartz glasscomponent.

For example, there has been proposed a method in which the deposit onthe surface of the quartz glass component, which is to be refurbished,consists of organic matter containing fluorine and is removed by using achemical such as dilute hydrofluoric acid or by a grinding process.After removal of the deposit, a reaction surface, which has been erodedand deteriorated in the plasma environment, and its opposite surface arethickened through welding quartz rods with an oxygen-hydrogen flameburner. Then, after grinding thickened sides into the predeterminedthickness, both surfaces are finished to an original state by precisionmachining and cleaning. (For example, see patent document 1.)

Another refurbishing method of the quartz glass component also has beenproposed. The quartz glass component with a step design on the surface,which is to be refurbished, having the reaction surface by plasma is cutnear the periphery thereof, and the plate-like portion including theeroded area is separated from the outer portion with no erosion. Then,the plate-like portion with the erosion area is discarded, and isrenewed with a new material that has almost the same shape as theoriginal. The new one is welded to the separated outer portion forrefurbishment. (For example, see patent document 2.)

Further, another refurbishing method of the quartz glass component hasbeen proposed. In a quartz glass component with a step design on thesurface, which is to be refurbished, a contamination layer of aplate-like portion including the eroded area is removed by a grindingprocess, and its surface is finished to mirror polish. Then, a new platehaving almost the same shape as the plate-like portion is manufactured,and the one side of the new plate is finished to mirror polish. Themirror surface of the new plate is contacted with the mirror surface ofthe existing component. The contact surface is bonded by applying a highpressure to each plate and by heating in a vacuum furnace to a hightemperature. (For example, see patent document 3)

However, the conventional method described above has the followingproblems. The surface deposit on the quartz glass component is removedby using a chemical such as dilute hydrofluoric acid or by a grindingprocess, and cleaning with a chemical such as dilute hydrofluoric acidis again performed to remove residual impurities before the flametreatment. Thus, the repetitive cleaning damages the surface of the basematerial, and significantly changes dimension and surface state of theportion in which refurbishment is not originally necessary. Moreover, itis difficult to confirm whether fine deposit remaining in microcracks onthe surface of the base material has been totally removed. Thus, qualityof the quartz glass component, relative to which the processingtreatment is to be performed, is not uniform.

The process of the above-described refurbishment method has thefollowing problem. Entire surfaces of the reaction surface and itsopposite side is thickened by flame-welding, so that the base materialis breakable due to the effect of thermal stress and strain generated ina wide area.

Moreover, there are the following problems for the refurbishment of thequartz glass component having a step design on the surface. Anewly-manufactured part is welded to the whole area of the joint of theexisting quartz glass component from which the contaminated portion hasbeen separated, thereby lowering the yield ratio and use efficiency ofquartz materials. Further, quartz material is breakable due to theeffect of thermal stress and strain generated in the wide area, so thatit requires much skill to weld the large area. Thus, such a processingtreatment results in the low productivity.

RELATED ART Patent Document

[Patent Document 1] Japanese Patent No. 4139184

[Patent Document 2] Japanese Published Unexamined Patent Application No.2005-67997

[Patent Document 3] Japanese Published Unexamined Patent Application No.2006-232624

SUMMARY OF THE INVENTION

It is an object of the present invention to solve the aforementionedproblems and provide a method of refurbishing a quartz glass component,in which the state of a deposit, erosion and deterioration of a quartzglass component that has been used in a certain process of semiconductormanufacturing, for example, is carefully checked before cleaning thequartz glass component, an appropriate cleaning method is determineddepending on the contamination status, the quartz glass component iscleaned with minimum damage to a base material, the residual deposit isprecisely checked to thereby carefully select the quartz glasscomponent, and a processing of refurbishment is carried out rationally.As a result, the refurbishment method can increase the mechanicalstrength of the quartz glass component which is made of brittlematerial, prevent breakage arising from growth of thermal stress andstrain during a flame treatment in a refurbishment process, enhance theproductivity and the yield ratio through efficient use of raw materialsof the quartz glass, stabilize the quality and rationalize therefurbishment.

The present invention provides a method of refurbishing a quartz glasscomponent as a first aspect thereof comprising:

performing a receiving inspection of a contaminated or eroded anddeteriorated quartz glass component;

irradiating the quartz glass component with light of a predeterminedwavelength to cause a fluorescence effect;

determining a cleaning method of the quartz glass component byinspecting a contamination status from a difference in fluorescent colorbetween the quartz glass component and a surface deposit;

performing a predetermined cleaning process of the quartz glasscomponent to remove the surface deposit depending on the contaminationstatus; and

-   restoring and refurbishing an eroded and deteriorated portion of the    cleaned quartz glass component by a flame treatment.

Accordingly, the contamination status of the quartz glass componentbefore cleaning is precisely and rationally checked, thereby selectingthe cleaning method depending on the state and carrying out the cleaningrationally.

The present invention provides a method of refurbishing a quartz glasscomponent as a second aspect thereof comprising:

irradiating the cleaned quartz glass component with the light of thepredetermined wavelength to cause the fluorescence effect, wherebyprocessability of the flame treatment for the cleaned quartz glasscomponent is determined by inspecting a presence or absence of residualimpurities from the difference in fluorescent color between the quartzglass component and the surface deposit.

Accordingly, the residual deposit of the cleaned quartz glass componentis precisely and rationally checked, processability of the flametreatment is rationally determined, and the quartz glass component whichis to be performed the flame treatment is carefully selected, therebymaintaining the quality of the quartz glass component and rationalizingthe processes of refurbishment.

According to a third aspect of the present invention, the quartz glasscomponent before or after the cleaning process is irradiated withultraviolet light of a wavelength range 200-400 nm. The light hasreliable and practical fluorescent properties.

According a fourth aspect of the present invention, the cleaning methodof the quartz glass component is selected from a combination of primaryand secondary cleaning processes, or from either the primary or thesecondary cleaning process depending on the contamination status whichis confirmed by the ultraviolet light irradiation. The cleaning can beselected from three types depending on the contamination status, therebyrealizing the rational cleaning. For example, when the quartz glasscomponent has been heavily contaminated, the component is cleaned bymeans of the combination of the primary and secondary cleanings. Whenthe component has been moderately contaminated, the cleaning method isselected from either the primary or the secondary cleaning process.Thus, the cleaning is rationalized.

According to a fifth aspect of the present invention, the primarycleaning process comprises spraying dry ice particles onto thecontaminated quartz glass component together with compressed air ornitrogen gas to peel off the surface deposit. Accordingly, the surfacedeposit is removed by cleaning the quartz glass component with minimumdamage to the base material.

According to a sixth aspect of the present invention, the secondarycleaning process comprises heating the contaminated quartz glasscomponent in a high-temperature furnace to sublime or incinerate thesurface deposit. Accordingly, the surface deposit is precisely removedwith minimum damage to the base material of the quartz glass component.

According to a seventh aspect of the present invention, colorationinside the quartz glass component, that is induced by solarization of aquartz glass material, is removed by the secondary cleaning process.Accordingly, appearance of the quartz glass component is restored andrefurbished.

According to an eighth aspect of the present invention, thehigh-temperature furnace is cooled down to contract and peel off thesurface deposit. Accordingly, the surface deposit is rationally removedwith minimum damage to the base material of the quartz glass component.

According to a ninth aspect of the present invention, the quartz glasscomponent is a chamber part for use in a plasma treatment apparatus forfabricating a semiconductor or liquid-crystal device. Accordingly, thecleaning and refurbishment are suitable for the quartz glass component,which is expensive and is a brittle material.

The present invention provides a method of refurbishing a quartz glasscomponent as a tenth aspect thereof comprising:

performing a receiving inspection of a contaminated or eroded anddeteriorated quartz glass component;

irradiating the quartz glass component, which has undergone thereceiving inspection, with light of a predetermined wavelength to causea fluorescence effect;

performing a predetermined cleaning process of the quartz glasscomponent to remove a surface deposit depending on a contaminationstatus;

irradiating the cleaned quartz glass component with light of thepredetermined wavelength to cause the fluorescence effect; and

-   restoring and refurbishing the eroded and deteriorated portion of    the cleaned quartz glass component, which has been considered to    necessitate that a flame treatment is processable by inspecting a    presence or absence of residual deposit through irradiation of light    of the predetermined wavelength, through-   either steps of separating the cleaned quartz glass component into    eroded and non-eroded portions depending on a state of erosion and    deterioration, and forming an integral structure by welding the    non-eroded portion with a new material including a remaining    material, where the new material is a substitute for the eroded    portion,-   or a step of flame-treating the cleaned quartz glass component    without separating the quartz glass component into the eroded and    non-eroded portions.

Accordingly, the quartz glass component is rationally cleaned, and theresidual deposit is carefully and rationally checked. In addition,relative to the quartz glass component which has been carefully selectedand considered as the flame treatment is processable, it is selecteddepending on the eroded state whether a step of separating the basematerial into the eroded and non-eroded portions is included or not. Inthe case of separating the base material into the eroded and non-erodedportions, the remaining material is utilized as a new material that is asubstitute for the eroded portion to be discarded. Therefore the yieldratio of the quartz material, which is expensive, is improved, therefurbishment process is rationalized, and the refurbishment cost isdecreased through efficient use.

The present invention provides a method of refurbishing a quartz glasscomponent as an eleventh aspect thereof comprising:

dividing the non-eroded portion, which has been separated from thequartz glass component, into several pieces;

dividing the new material containing the remaining material into severalpieces; and forming an integral structure by welding the divided piecesof each portion for refurbishment.

Accordingly, the refurbishment is rationalized, the mechanical strengthagainst thermal stress and strain is increased, the productivity isincreased, and the material lasts longer.

The present invention provides a method of refurbishing a quartz glasscomponent as a twelfth aspect thereof comprising:

smoothing surfaces of the divided pieces of the non-eroded portion andthe new material by flame treatment; and

forming an integral structure by welding the divided pieces forrefurbishment.

Accordingly, mechanical strength of the component parts before beingsubjected to the flame treatment is increased to resist thermal stressand strain due to the flame treatment, and mechanical strength of thequartz glass component, which is a brittle material, is increased.

The present invention provides a method of refurbishing a quartz glasscomponent as a thirteenth aspect thereof comprising:

dividing the quartz glass component in a coexistent state of the erodedand non-eroded portions into several pieces without separating thequartz glass component into the eroded and non-eroded portions;

directly flame-treating an eroded side of the divided piece to increasethickness of the quartz glass component; and

forming an integral structure by welding the thickened pieces to eachother.

Accordingly, the quartz glass component is easily and promptlyprocessed, and mechanical strength against thermal stress and strain isincreased as compared with a conventional refurbishment process in whichthe eroded and deteriorated portion is grinded and then the oppositeside is thickened by welding quartz rods.

According to a fourteenth aspect of the present invention, the erodedportion of the quartz glass component is thickened by directlyflame-welding quartz rods without the step of separating the quartzglass component into the eroded and non-eroded portions. Accordingly,the quartz glass component is easily and promptly processed incomparison with a conventional refurbishment process in which the erodedand deteriorated portion is grinded and then the opposite side isthickened by welding quartz rods.

According to a fifteenth aspect of the present invention, the newmaterial containing the remaining material has a ring-like, discoidshape, or has a shape divide therefrom. Accordingly, the remainingmaterials are used effectively, and the quartz glass component isrefurbished rationally and at lower cost.

According to a sixteenth aspect of the present invention, the quartzglass component is a chamber part for use in a plasma treatmentapparatus for fabricating a semiconductor or liquid-crystal device.Accordingly, the cleaning and refurbishment are suitable for the quartzglass component, which is expensive and is a brittle material.

TECHNICAL ADVANTAGE OF THE INVENTION

In the first aspect of the present invention, the quartz glass componentis irradiated with light of a predetermined wavelength to cause afluorescence effect, and a cleaning method of the quartz glass componentdetermined by inspecting a contamination status from a difference influorescent color between the quartz glass component and the surfacedeposit. Accordingly, the contamination status of the quartz glasscomponent before cleaning is precisely and rationally checked, so thatit is possible to select the cleaning method depending on the state andcarry out the cleaning rationally.

In the second aspect of the present invention, the cleaned quartz glasscomponent is irradiated with the light of the predetermined wavelengthto cause the fluorescence effect, whereby processability of the flametreatment for the cleaned quartz glass component is determined byinspecting a presence or absence of the residual impurities from thedifference in fluorescent color between the quartz glass component andthe surface deposit. Accordingly, the residual deposit of the cleanedquartz glass component is precisely and rationally checked,processability of the flame treatment is rationally determined, and thequartz glass component, relative to which the flame treatment is to beperformed, is carefully selected, so that it is possible to maintain thequality of the quartz glass component and rationalize the processes ofrefurbishment.

According to the third aspect of the present invention, the quartz glasscomponent before or after the cleaning process is irradiated withultraviolet light of a wavelength range 200-400 nm. The light hasreliable and practical fluorescent properties. In addition, anappropriate cleaning method can be selected, and a presence or absenceof the residual deposit can be reliably confirmed.

According the fourth aspect of the present invention, the cleaningmethod of the quartz glass component is selected from a combination ofprimary and secondary cleaning processes, or from either the primary orthe secondary cleaning process depending on the contamination statuswhich is confirmed by the ultraviolet light irradiation. The cleaningcan be selected from three types depending on the contamination status,thereby realizing the rational cleaning. For example, when the quartzglass component has been heavily contaminated, the component is cleanedby means of the combination of the primary and secondary cleanings. Whenthe member has been moderately contaminated, the cleaning method isselected from either the primary or the secondary cleaning process.Thus, the cleaning is rationalized.

According to the fifth aspect of the present invention, the primarycleaning process comprises spraying dry ice particles onto thecontaminated quartz glass component together with compressed air ornitrogen gas to peel off the surface deposit. Accordingly, the surfacedeposit is removed by cleaning the quartz glass component with minimumdamage to the base material.

According to the sixth aspect of the present invention, the secondarycleaning process comprises heating the contaminated quartz glasscomponent in a high-temperature furnace to sublime or incinerate thesurface deposit. Accordingly, the surface deposit is precisely removedwith minimum damage to the base material of the quartz glass component.

According to the seventh aspect of the present invention, colorationinside the quartz glass component, that is induced by solarization ofthe quartz glass material, is removed by the secondary cleaning process.Accordingly, appearance of the quartz glass component is restored andrefurbished.

According to the eighth aspect of the present invention, thehigh-temperature furnace is cooled down to contract and peel off thesurface deposit. Accordingly, the surface deposit is rationally removedwith minimum damage to the base material of the quartz glass component.

According to the ninth aspect of the present invention, the quartz glasscomponent is a chamber part for use in a plasma treatment apparatus forfabricating a semiconductor or liquid-crystal device. Accordingly, thecleaning and refurbishment are suitable for the quartz glass component,which is expensive and is a brittle material.

In the tenth aspect of the present invention, the method of refurbishingthe quartz glass component comprises steps of irradiating the cleanedquartz glass component with light of the predetermined wavelength tocause the fluorescence effect; and

-   restoring and refurbishing the eroded and deteriorated portion of    the cleaned quartz glass component, which has been considered to    necessitate that a flame treatment is processable by inspecting a    presence or absence of the residual deposit through irradiation of    light of the predetermined wavelength, through either steps of    separating the cleaned quartz glass component into eroded and    non-eroded portions depending on a state of erosion and the    deterioration, and forming an integral structure by welding the    non-eroded portion with a new material including a remaining    material, where the new material is a substitute for the eroded    portion, or a step of flame-treating the cleaned quartz glass    component without separating the quartz glass component into the    eroded and non-eroded portions. Accordingly, the quartz glass    component is rationally cleaned, and the residual deposit is    carefully and rationally checked. In addition, relative to the    quartz glass component which has been carefully selected and    considered as the flame treatment is processable, it is selected    depending on the eroded state whether a step of separating the base    material into the eroded and non-eroded portions is included or not.    In the case of separating the base material into the eroded and    non-eroded portions, the remaining material is utilized as a new    material that is a substitute for the eroded portion to be    discarded. Therefore, the yield ratio of the quartz material, which    is expensive, is improved, the refurbishment process is    rationalized, and the refurbishment cost is decreased through    efficient use.

The present invention provides a method of refurbishing a quartz glasscomponent as the eleventh aspect thereof comprising a step of dividingthe non-eroded portion and new material into several pieces, and formingan integral structure by welding the divided pieces of each portion forrefurbishment. Accordingly, the refurbishment is rationalized, themechanical strength against thermal stress and strain is increased, theproductivity is increased, and the material lasts longer.

The present invention provides a method of refurbishing a quartz glasscomponent as the twelfth aspect thereof comprising a step of smoothingsurfaces of the divided pieces of non-eroded portion and the newmaterial by flame treatment, and forming an integral structure bywelding the divided pieces of each portion for refurbishment.Accordingly, mechanical strength of the component parts before beingsubjected to the flame treatment is increased to resist thermal stressand strain due to the flame treatment, and mechanical strength of thequartz glass component, which is a brittle material, is increased.

The present invention provides a method of refurbishing a quartz glasscomponent as the thirteenth aspect comprising a step of dividing thequartz glass component in a coexistent state of the eroded andnon-eroded portions into several pieces without separating the quartzglass component into the eroded and non-eroded portions, directlyflame-treating an eroded side of the divided piece to increase inthickness of the quartz glass component, and forming an integralstructure by welding the thickened pieces to each other. Accordingly,the quartz glass component is easily and promptly processed, andmechanical strength against thermal stress and strain is increased ascompared with a conventional refurbishment process in which the erodedand deteriorated portion is grinded and then the opposite side isthickened.

According to the fourteenth aspect of the present invention, the erodedportion of the quartz glass component is thickened by directlyflame-welding quartz rods without the step of separating the quartzglass component into the eroded and non-eroded portions. Accordingly,the quartz glass component is easily and promptly processed incomparison with a conventional refurbishment process in which the erodedand deteriorated portion is grinded and then the opposite side isthickened.

According to the fifteenth aspect of the present invention, the newmaterial containing the remaining material has a ring-like, discoidshape, or has a shape divided therefrom. Accordingly, the remainingmaterials are used effectively, and the quartz glass component isrefurbished rationally and at lower cost.

According to the sixteenth aspect of the present invention, the quartzglass component is a chamber part for use in a plasma treatmentapparatus for fabricating a semiconductor or liquid-crystal device.Accordingly, the cleaning and refurbishment are suitable for the quartzglass component, which is expensive and is a brittle material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1( a) is a plan view of the eroded and deteriorated quartz glasscomponent to which a first embodiment of the present invention isapplied. FIG. 1( b) is a cross sectional view taken along line I(b)-I(b)in FIG. 1( a).

FIG. 2 shows a refurbishment process flowchart of the first embodiment.

FIG. 3 shows refurbishment steps of an outline of the first embodiment.FIG. 3( a) is a perspective view of the contaminated and deterioratedquartz glass component that has not been subjected to the refurbishmentprocess. FIG. 3( b) is a perspective view of the non-eroded portion(outer ring) in which the eroded portion of the quartz glass componenthas been cut. FIG. 3( c) is a perspective view of a new inner ring thatis a substitute for the eroded portion. FIG. 3( d) is a perspective viewshowing a state in which the outer ring is divided into parts. FIG. 3(e) is a perspective view showing a state in which the new inner ring isdivided into parts. FIG. 3( f) is a perspective view showing a state ofchamfering of the divided parts of the inner and outer rings. FIG. 3( g)is a perspective view showing a state in which the divided parts of theinner and outer rings in pairs are welded to each other. FIG. 3( h) is aperspective view of a refurbished prototype ring completed by weldingfour pairs of the divided parts of the inner and outer rings.

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 3(h).

FIG. 5 is an enlarged sectional view taken along line V-V in FIG. 3( h).

FIG. 6 is an enlarged sectional view taken along line VI-VI in FIG. 3(h).

FIG. 7 shows a refurbishment process flowchart of the second embodimentof the present invention.

FIG. 8 is a view of refurbishment steps that shows an outline of thesecond embodiment. FIG. 8( a) is a perspective view of the contaminatedand deteriorated quartz glass component before being subjected to therefurbishment process. FIG. 8( b) is a perspective view showing a statein which the quartz glass component having the eroded and non-erodedportions in coexistence has been cut. FIG. 8( c) is a perspective viewshowing a state of chamfering of the divided part. FIG. 8( d) is aperspective view showing a state in which the eroded portion of thedivided part has been thickened. FIG. 8( e) is a perspective view of arefurbished prototype ring completed by welding four pairs of thethickened divided parts.

FIG. 9 is an enlarged sectional view taken along line IX-IX in FIG. 8(e).

FIG. 10 is an enlarged sectional view taken along line X-X in FIG. 8(e).

FIG. 11 is an enlarged sectional view taken along line XI-XI in FIG. 8(e).

FIG. 12 shows a refurbishment process flowchart of the third embodimentof the present invention.

FIG. 13 is a view of refurbishment steps that shows an outline of thethird embodiment. FIG. 13( a) is a perspective view of the contaminatedand deteriorated quartz glass component before being subjected to therefurbishment process. FIG. 13( b) is a perspective view showing a statein which a part of the eroded and deteriorated portion has beenthickened. FIG. 13( c) is a perspective view of a refurbished prototypering completed by thickening the whole area of the eroded anddeteriorated portion.

FIG. 14 is an enlarged sectional view taken along line XIV-XIV in FIG.13( c).

FIG. 15 is an enlarged sectional view taken along line XV-XV in FIG. 13(c).

FIG. 16( a) is a plan view of a ring-like component of the fourthembodiment of the present invention. FIG. 16( b) is a sectional viewtaken along line XVI(b)-XVI(b) in FIG. 16( a).

FIG. 17( a) is a plan view of a discoid component of the fourthembodiment of the present invention. FIG. 17( b) is a sectional viewtaken along line XVII(b)-XVII(b) of the FIG. 17( a).

DETAILED DESCRIPTION OF THE INVENTION

The following is a description of illustrated embodiments that thisinvention is applied to refurbishment of the quartz glass component,which is a chamber part in a plasma treatment apparatus for fabricatinga semiconductor or liquid-crystal device. In FIG. 1 to FIG. 6, referencenumeral 1 is the quartz glass component with step design on the surface,which is to be refurbished, having been eroded and deteriorated due to along period of use in the plasma treatment apparatus. A large-diameterstep 2 is formed on the opposite side of a reaction surface 1 a, whichis to be subjected to a plasma environment, and a through-hole 3 isformed at the center thereof.

The eroded and deteriorated portion 4 of the quartz glass component 1 inthe embodiment can be restored and refurbished. When the eroded anddeteriorated portion 4 is eroded out and unusable, the portion isdiscarded after separating from the base material and a new quartz glassmaterial as substitute for the portion is integrally welded forrefurbishment.

The present invention is applicable to a ring-like component (FIG. 16)or a discoid component (FIG. 17), which will be described later, inaddition to the quartz glass component 1 having the step design.

Substantially the whole area of the reaction surface 1 a is eroded anddeteriorated in the plasma environment and the deposit 5 remains at theeroded and deteriorated portion 4 and the inner surface of thethrough-hole 3.

In a case of a plasma etching treatment apparatus of a silicon oxidefilm formed on a semiconductor wafer, for example, the deposit 5consists of organic matters including fluorine.

When the quartz glass component 1 is exposed to the plasma environmentover a long time, the base material may become tinged with purple bysolarization. The coloration is simultaneously removed byhigh-temperature heat cleaning, which will be described later.

The solarization is a coloration phenomenon caused by a small amount ofmetal impurities contained in the quartz glass material and is notremoved by normal chemical cleaning since it is not an object attachedonto the surface.

The experiment conducted by the inventors demonstrates that thecoloration is removed by maintaining the base material of the quartzglass component at a predetermined temperature or higher.

In FIG. 1, reference numeral 6 represents a tapered surface formed onone side of the periphery of the quartz glass component 1. Referencesymbol L represents a section line provided at the outer side of theeroded and deteriorated portion 4. The quartz glass component 1 is cutalong the section line L, the inner portion of the quartz glasscomponent 1 which includes the cut, eroded and deteriorated portion 4 isdiscarded, and the outer portion which does not include the eroded anddeteriorated portion 4 is reutilized.

The refurbishment process of the quartz glass component 1 is shown inFIG. 2. Firstly, the quartz glass component 1, which needs to berefurbished, is inspected when it is received. Then, the quartz glasscomponent is visually checked with respect to the deposit 5,contamination, deterioration, and coloration state due to solarizationto determine the processability of refurbishment.

After the receiving inspection, the quartz glass component 1 isirradiated with ultraviolet light having a fluorescence effect, forexample, and having a wavelength of from 200 to 400 nm by using anon-destructive test apparatus (not shown). The range of thecontamination, which is unable to recognize under the visible light suchas white light, is checked from the difference in fluorescence betweenthe quartz glass component 1 and the deposit 5.

More specifically, when ultraviolet light having a wavelength of 254 nmis irradiated, a natural quartz glass fluoresces blue. When ultravioletlight having a wavelength of 365 nm is irradiated, organic matters,which are main components of the deposit 5, fluoresce yellow, red, andgreen. By checking these colors visually, the existence of the depositcan be judged precisely and rationally.

After checking the deposit, when the quartz glass component is heavilycontaminated due to the attachment of a large amount of the deposit, forexample, the quartz glass component is cleaned by means of combinationof the primary and secondary cleaning methods. When the quartz glasscomponent is moderately contaminated due to the attachment of a smallamount of the deposit, the quartz glass component is cleaned by means ofthe primary or secondary cleaning method.

In the embodiment, dry ice blast cleaning is adopted as the primarycleaning and high-temperature heat cleaning is adopted as the secondarycleaning.

In the dry ice blast cleaning, the quartz glass component 1 is placedinto a clean chamber (not shown), and the high-purity dry ice particles,which have temperatures of minus 70 degrees Celsius or lower, aresprayed onto the quartz glass component 1 together with compressed cleanair or nitrogen gas through a blast machine (not shown).

In the embodiment, the injection pressure of the dry ice blasting is setto be from 0.2 to 0.5 MPa.

Then, the surface of the quartz glass component 1 is cooled by the dryice blasting. When the dry ice particles vaporize, the deposit 5 ispeeled off by heat contraction, whereby the deposit 5 is removed withoutdamaging the quartz glass component 1.

In the high-temperature heat cleaning, the quartz glass component 1,which has been subjected to the primary cleaning or which has beenomitted the primary cleaning, is placed into the high-temperaturecleaning furnace (not shown). The high-temperature cleaning furnace isheated to temperatures of about 700 to 1050 degrees Celsius in air,vacuum, or inert gas atmosphere to sublime or incinerate the tinydeposit 5 or the contamination. The purplish coloration of the quartzglass component 1 due to solarization is removed simultaneously.

The solarization is a coloration phenomenon caused by a small amount ofmetal impurities contained in the base material of the quartz glasscomponent and is not removed by normal chemical cleaning since it is notan object attached onto the surface.

The experiment conducted by the inventors demonstrates that thecoloration is removed by maintaining the base material of the quartzglass component at-least 600 degrees Celsius or higher.

Accordingly, when the quartz glass component 1 on which the deposit 5remains and which is colored due to solarization is cleaned by heating,the temperature is raised until the coloration is removed, that is 700degrees Celsius or higher, which is 600 degrees Celsius plus somethingextra, whereby both the deposit and the coloration can be removedrationally.

In this case, organic matters constituting the deposit 5 are oxidized attemperatures of about 400 degrees Celsius or higher, and solarization isremoved at temperatures of about 700 degrees Celsius or higher. Thelower limit of the temperature in the high-temperature cleaning furnaceis set to 700 degrees Celsius. On the other hand, a strain point ofquartz glass material is around 1100 degrees Celsius, so that the upperlimit of the temperature in the high-temperature cleaning furnace is setto 1050 degrees Celsius to prevent thermal deformation of the basematerial.

In the cool-down process of the high-temperature heat cleaning, thedeposit 5 is peeled off by a difference of coefficients of thermalexpansion of the deposit 5 and the quartz glass component 1.

In this case, in addition to the so-called dry cleaning, it is possibleto adopt a wet cleaning that the quartz glass component 1 is immersed ina chemical such as acid, alkali, and an organic solvent. Further, thequartz glass component may be cleaned by means of a combination of thedry and wet cleaning processes.

The dimension and appearance of the quartz glass component 1, in whichthe deposit 5 and the coloration due to solarization have been removedin the described manner, is visually checked in an interim check. Thequartz glass component 1 is irradiated with ultraviolet light having awavelength of from 200 to 400 nm by using the non-destructive testapparatus (not shown). Thus, the presence or absence of the residual ofthe deposit 5, that is the result of the cleaning, is visually checkedprecisely and rationally from the difference in fluorescent colorbetween the quartz glass component 1 and the deposit 5. Further, thecontamination area which is invisible at optical wavelengths can beassessed by the above manner.

The quartz glass component 1 is considered as being refurbished when thedeposit 5 remains in a predetermined amount or less. The quality andproductivity are improved by selecting the refurbishable quartz glasscomponent 1 carefully, and refurbishment processing is carried outrationally.

In this case, when the quartz glass component 1 is moderately eroded andthe later-described refurbishment process is considered unnecessaryafter performing the receiving inspection or the interim check for thequartz glass component 1, the eroded and deteriorated portion 4 isrestored and refurbished by a series of the cleaning steps to remove thedeposit 5 and/or the coloration due to solarization. After this, therefurbishment treatment is finished by means of mechanical processingwhen necessary.

On the other hand, after the receiving inspection or the interim check,when the eroded and deteriorated portion 4 of the quartz glass component1 needs to be restored or refurbished, the after-mentioned refurbishmentprocess is performed.

In the refurbishment process, various kinds of refurbishment processesare adopted based on the shape and dimension of the quartz glasscomponent 1, the state of the eroded and deteriorated portion 4, theoperating conditions of the refurbishment processing, processing time,and cost.

As described above, the eroded and deteriorated portion 4 of the quartzglass component 1 in the embodiment is severely eroded and is unable touse. Thus, a refurbishment method is adopted in which the eroded anddeteriorated portion 4 is discarded, and a new quartz glass material isintegrated by welding for recovery.

The following outlines the refurbishment process. After separating theeroded and deteriorated portion and the non-eroded portion, the erodedand deteriorated portion is replaced with a new material. Then, thenon-eroded portion and the new material are integrated by flame-welding.This state is shown in FIG. 3.

In the refurbishment process, firstly, the quartz glass component 1 iscut along the section line L by appropriate means. A deterioratedportion that is inside of the section line L and includes the eroded anddeteriorated portion 4 is discarded, and the non-eroded portion that isoutside of the section line L is reutilized. The outer ring 7 in theembodiment has an outside diameter of 400 mm and an inside diameter ofabout 350 mm.

Then, the outer ring 7 is divided into pieces by appropriate means.

The number of pieces is determined on the basis of the after-mentionedflame treatment, operating conditions, and the size of the outer ring 7.For example, a ring having similar shape and size to the one used in theembodiment is divided into four pieces. A ring smaller than the one usedin the embodiment is divided into two to three pieces and a ring largerthan the same is divided into four pieces or more.

In FIG. 3, reference numeral 7 a represents a piece of the divided outerring 7.

A new inner ring 8 is prepared as a substitute for the eroded anddeteriorated portion 4 which is to be discarded. The inner ring 8 isdivided in the same number as the outer ring 7.

The inner ring 8 has substantially the same diameter as the section lineL. The ring is made of a plate and the thickness thereof is determinedby considering the machining allowance. The center of the plate isformed with a hole that is smaller than the aforementioned through-hole3.

In this case, as described above, a new quartz glass material may beused for the inner ring 8. However, when manufacturing the new quartzglass material, a remaining material of quartz glass having a shape of aring, disc, or plate, or another remaining material of quartz glassdivided therefrom is generated. Thus, by using the remaining material ofquartz glass for the inner ring 8 or an inner ring piece, which will bedescribed later, the refurbishment can be carried out rationally and therefurbishment cost is reduced. Accordingly, the remaining material ofquartz glass needs to have similar purity to the new remaining materialof quartz glass and may be formed at any time.

The inner ring 8 is divided into pieces in the same number as the outerring 7. The inner ring piece 8 a is formed through dividing the innerring 8 into four equal parts.

Then, the surfaces of the joined and welded portions of the outer andinner ring pieces 7 a, 8 a are chamfered with appropriate means to betapered.

In FIG. 3, reference numeral 7 b represents a tapered chamfered-portionformed on both ends of the outer ring piece 7 a. Reference numeral 7 crepresents a tapered chamfered-portion formed on the inner surface ofthe outer ring piece 7 a. Reference numeral 8 b represents a taperedchamfered-portion formed on both ends of the inner ring piece 8 a.Reference numeral 8 c represents a tapered chamfered-portion formed onthe outer surface of the inner ring piece 8 a. This state is shown inFIG. 3( f).

Then, the outer ring piece 7 a and the inner ring piece 8 a are cleanedwith hydrofluoric acid and de-ionized water. After flame finishing them,internal strain is removed by annealing.

The ring pieces are flame finished with an oxygen-hydrogen flame burner(not shown). Forming a flame at the nozzle exist, the flame is appliedto the outer ring piece 7 a and the inner ring piece 8 a and heated toabout 2000 degrees Celsius. Microcracks are melted to smoothen thesesurfaces. After enhancing mechanical strength, they are placed in anelectric furnace for annealing to remove internal strain.

The outer and inner ring pieces 7 a, 8 a in pairs are arranged, theouter ring 7 a being arranged externally of the inner ring 8 a. They arejointed to each other by welding quartz glass rods (not shown) inwelding spaces, which are generally V-shaped grooves formed by thefacing chamfered portions 7 c, 8 c, This state is shown in FIG. 3( g),and the outer and the inner ring pieces 7 a, 8 a are formed in agenerally fan-shape.

The ring pieces are welded with the oxygen-hydrogen flame burner (notshown). Forming a flame having a temperature of about 2000 degreesCelsius, the flame is applied to quartz glass rod, and the melted quartzglass is filled in a welding space. In FIG. 3, reference numeral 9represents a welding bead in which the melted quartz glass issolidified.

Then, other pairs of the outer and inner ring pieces 7 a, 8 a are weldedin the similar manner, four pairs of the ring pieces 7 a, 8 a are weldedin total. After welding, the outer ring piece 7 a and inner ring piece 8a are placed in an electric furnace for annealing to remove strain.After removing strain, the ring pieces are cleaned with hydrofluoricacid and de-ionized water.

The edges of the welded four pairs of the outer and inner ring pieces 7a, 8 a are arranged in a ring shape. They are welded to each other bymelting quartz rods, as previously described, in welding spaces whichare the generally V-shape grooves formed by the facing chamferedportions 7 b, 7 b and 8 b, 8 b, respectively. In FIG. 3, referencenumeral 10 represents a welding bead for welding the end faces of theouter and the inner ring pieces 7 a, 8 a. The welding bead 10 is widerand higher than the aforementioned welding bead 9.

This state is shown in FIG. 3( h). A refurbished prototype ring iscompleted as a consequence of connecting four pairs of the outer andinner ring pieces 7 a, 8 a in a ring shape.

Then, the refurbished prototype ring is placed in an electric furnace toremove strain by annealing. After this, refurbishment process is to bemoved from the hot process focusing on the flame treatment to machiningprocess forming the ring into a predetermined shape, size, and surfaceroughness.

In the machining process, by using a grinding machine, machining center,lathe, and sandblast, the thickness, inside and outside diameters, andtapered surface of the refurbished ring are machined to form the ringinto a predetermined shape, size, and surface roughness. Then, themachining process of the refurbished ring is finished.

Then, after the refurbished ring is cleaned, the appearance and thedimension are checked in a final inspection. A series of refurbishmentprocesses are completed after the final cleaning.

As described above, in the refurbishment process, the refurbishedprototype ring is formed by separating the quartz glass component 1 intothe eroded portion and the non-portion, replacing the eroded portionwith the new quartz glass material which includes a remaining material,dividing the non-eroded portion and the new material into parts whenrefurbishing the quartz glass component by subjecting them to the flametreatment and welding them, welding and annealing a pair of the dividedparts, and arranging a plurality of pairs in a ring-shape and weldingthese integrally.

Accordingly, the method can reduce thermal stress and strain of thenon-eroded portion and the new material, prevent generation of a crackwhen welding them or using a refurbished material, facilitaterefurbishment and flame treatment, and enhance productivity as comparedwith a method in which the non-eroded portion and the new material,which are not divided, are welded together after subjecting them toflame treatment.

The refurbishment process facilitates rational use of various remainingmaterials having a ring-like or discoid shape as the new material,further having a divided shape of them, and thereby can improve theyield ratio of the quartz glass component 1, reduce the refurbishmentcost and improve the productivity.

On the other hand, the above-described refurbishment process is suitablefor quartz glass material, which is a brittle material, dividing thenon-eroded portion and the new material into parts and welding them todisperse remaining small internal stress and strain, preventing growthof internal stress and strain and generation of a crack, and increasingmechanical strength.

FIG. 7 to FIG. 17 show other embodiments of the present invention. Thecomponents and the parts corresponding to the aforementioned structuresare denoted by the same reference numerals.

Of these figures, FIG. 7 to FIG. 11 show main points of the secondembodiment of the present invention. In the embodiment, the quartz glasscomponent 1 can be used if mended because the eroded and deterioratedportion 4 is not so heavily deteriorated as to be discarded, unlike theaforementioned one which is unable to be refurbished.

The refurbishment process for the quartz glass component 1 is shown inFIG. 7. The receiving inspection before subjecting the quartz glasscomponent to the refurbishment process, the contamination check, how toremove the deposit, and the interim check are performed in the samemanner as the aforementioned embodiment. Only the flame treatment in therefurbishment process is performed differently and the outline of theflame treatment is shown in FIG. 8.

Specifically, the second embodiment is applied to the quartz glasscomponent 1, which is similar to the embodiment as described above,having a step design on the surface. The quartz glass component 1, whichhas been carefully selected in the receiving inspection and the interimcheck, is divided radially into parts with appropriate means.

Accordingly, unlike the first embodiment, the eroded and deterioratedportion 4 does not need to be cut in a round shape along the sectionline L. The shape of the quartz glass component 1 is not limited to thering with the step design, and a ring or disc without the step design,which will be described later, is also adoptable.

The quartz glass component 1 is divided in the same manner as in theaforementioned embodiment. The ends of the joined or welded portion ofthe divided part 1 b are tapered by chamfering. After cleaning them withhydrofluoric acid and de-ionized water, they are flame-finished.Further, internal strain is removed by annealing. The divided part 1 bis flame-finished in the same manner as in the embodiment previouslydescribed and mechanical strength is enhanced.

Next, the eroded and deteriorated portion 4 of the divided part 1 b thathas been annealed is thickened with an oxygen-hydrogen flame burner (notshown). The flame at the nozzle exit of the burner having a temperatureof about 2000 degrees Celsius is applied to the quartz glass rod and themelted quartz glass is used to thicken the eroded and deterioratedportion 4. The inner surface of the eroded through-hole 3 is thickened.This state is shown in FIG. 8( d) and FIG. 9.

In the embodiment, the melted quartz glass is formed like a bead in aradial direction into the quartz glass thickened portion 11, the otherdivided parts 1 b are thickened in the same manner, the four dividedparts 1 b are thickened in the same thickness, and the inner surface ofthe through-hole 3 is formed with the thickened portion 11. Then, theyare placed in an electric furnace for annealing to remove strain. Afterremoving strain, they are cleaned with hydrofluoric acid and de-ionizedwater.

Then, the thickened four divided parts 1 b are arranged in a ring shape.They are welded to each other by melting quartz glass, as previouslydescribed, in a generally V-shaped welding space formed by the facingchamfered portions 1 c, 1 c and 1 d, 1 d, respectively.

This state is shown in FIG. 8( e). A refurbished prototype ring iscompleted as a consequence of welding the four divided parts 1 b in aring shape.

As described above, in the refurbishment process in the secondembodiment, the quartz glass component 1 is divided and the eroded anddeteriorated portion of the divided part 1 b is thickened by directlyflame-welding for refurbishment without separating the quartz glasscomponent 1 into the eroded portion and the non-eroded portion andwithout substituting the eroded portion with a new material.

Accordingly, the operations in the first embodiment, such as those ofcutting along the eroded and deteriorated portion 4, procurement of theinner ring 8, which is a new material, dividing of the outer and innerrings 7, 8, chamfering of the outer and inner ring pieces 7 a, 8 a, andwelding are omitted. Thus, the operations can be easily and rationallyperformed and the productivity will be increased.

In the refurbishment process of the second embodiment, the eroded anddeteriorated portion of the divided part 1 b is thickened by directlyflame-welding. Thus, this reduces labor of grinding and the parts arethickened easily and promptly as compared with a conventionalcomplicated method that includes the steps of removing the erodedportion by grinding and thickening the opposite surface of the grindedsurface.

Moreover, compared with the conventional method in which the whole areaof one surface of the quartz glass component is thickened, this methodprevents concentration of thermal stress and strain by thickening eachof the divided parts 1 b. This method also has advantage that therefurbishment and flame treatment is made easier and productivity isenhanced because generation of a crack during welding work is prevented.

The above-described refurbishment process is suitable for refurbishingthe quartz glass component 1, which is a brittle material, dividing andwelding the non-eroded portion, dispersing remaining small internalstress and strain and reducing them, preventing growth of internalstress and strain and generation of a crack, and thereby improvingmechanical strength.

FIGS. 12 to 15 show main points of the third embodiment. This embodimentcorresponds to an applied embodiment of the aforementioned secondembodiment.

This embodiment is applied, in the same manner as previously described,to the quartz glass component 1 having a step design on the surface. Theeroded and deteriorated portion 4 is directly thickened and the innersurface of the through-hole 3 is thickened without dividing the quartzglass component 1 into pieces, which has been carefully selected in thereceiving inspection. Accordingly, chamfering, flame finishing, andwelding of the divided parts are unnecessary.

The quartz glass component is thickened in the same manner as in thesecond embodiment. A refurbished prototype ring is completed withoutneed of annealing each of the thickened portions.

Accordingly, in the refurbishment process of the third embodiment, thequartz glass component 1 which has been carefully selected in thereceiving inspection can be promptly thickened without dividing thequartz glass component 1. Thus, the quartz glass component can be easilyand rationally refurbished and productivity will be enhanced.

FIGS. 16-17 show main points of the fourth embodiment. This embodimentis applied to the ring-shaped quartz glass component 1 in FIG. 16 and tothe discoid quartz glass component 1 in FIG. 17 instead of the quartzglass component 1 having a step design on the surface. The concreteprocess of refurbishment is similar to the aforementioned embodiment.

As discussed above, in the method of refurbishing a quartz glasscomponent, in which the state of a deposit, erosion and deterioration ofa quartz glass component that has been spent by using in a certainprocess of semiconductor manufacturing, for example, is carefullychecked before cleaning the quartz glass component, the appropriatecleaning method is determined depending on the contamination status, thequartz glass component is cleaned with minimum damage to a basematerial, the residual deposit is precisely checked to thereby carefullyselect the quartz glass component and carry out refurbishmentrationally. As a result, the refurbishment method can increase themechanical strength of the quartz glass component which is a brittlematerial, prevent breakage arising from growth of strain and thermalstress during a flame treatment in a refurbishment process, enhance theproductivity and the yield ratio through efficient use of the quartzglass material, stabilize the quality and rationalize the refurbishment.

The invention claimed is:
 1. A method of refurbishing a quartz glasscomponent in an eroded or contaminated and deteriorated state,comprising: inspecting an eroded or contaminated and deteriorated quartzglass component by irradiating same with ultraviolet light of awavelength of 200-380 nm to cause a fluorescence effect; determining anerosion or contamination status through visual inspection of differencesin fluorescing colors visible upon irradiation of the eroded orcontaminated and deteriorated quartz glass component, the colors beingattributable to surface deposit on the eroded or contaminated anddeteriorated quartz glass component and to the quartz glass of theeroded or contaminated and deteriorated quartz glass component;performing a predetermined cleaning method on the eroded or contaminatedand deteriorated quartz glass component based on the erosion orcontamination status, the predetermined cleaning method being a primarycleaning method that is a dry ice blast cleaning comprising peeling offthe surface deposit by spraying dry ice particles onto the eroded orcontaminated and deteriorated quartz glass component together withcompressed air or compressed nitrogen gas and utilizing thermalcontraction to effect removal of the surface deposit; whereby, afterperforming the predetermined cleaning method, a cleaned quartz glasscomponent is obtained; checking the erosion or contamination status ofthe cleaned quartz glass component by irradiating the cleaned quartzglass component with ultraviolet light and visually inspecting thecleaned quartz glass component; and performing a post-cleaning treatmentselected from a removal and replacement treatment in which a portion ofthe cleaned quartz glass component is removed and replaced with areplacement portion of new quartz glass material and a flame treatmentwithout the removal and replacement treatment, wherein the post-cleaningtreatment is a removal and replacement treatment comprising the steps ofseparating the cleaned quartz glass component into an eroded portion anda non-eroded portion, discarding the eroded portion, substituting theeroded portion with a replacement portion of new quartz glass material,dividing the non-eroded portion separated from the quartz glasscomponent into divided pieces of the non-eroded portion, dividing thenew quartz glass material into divided pieces of the new quartz glassmaterial, forming parts by welding the divided pieces of the non-erodedportion and the divided pieces of the new quartz glass material, andwelding the parts to form an integral structure.
 2. The method accordingto claim 1, wherein the post-cleaning treatment is a removal andreplacement treatment comprising the steps of providing a number ofreplacement portions of new quartz glass material that are equal to anumber of divided pieces of the non-eroded portion and pairing theportions of new quartz glass material and divided non-eroded portions,whereby pairs are formed; welding surfaces of the pairs to form parts:and welding the parts to form an integral structure for refurbishment.3. The method according to claim 2, wherein the new quartz glassmaterial has a ring shape, discoid shape, or polygonal shape, or has ashape divided therefrom.
 4. The method according to claim 1, wherein thenew quartz glass material includes new quartz glass material remainingafter manufacturing other quartz glass components from new quartz glassmaterial.
 5. The method according to claim 1, wherein the eroded orcontaminated and deteriorated quartz glass component is a chamber partfor use in a plasma treatment apparatus for fabricating a semiconductoror liquid-crystal device.
 6. The method according to claim 1, whereinthe quartz glass component is step-, ring-, or disc-shaped.
 7. Themethod according to claim 1, wherein the new quartz glass material has aring shape, discoid shape, or polygonal shape, or has a shape dividedtherefrom.
 8. The method according to claim 1, further comprising thestep of smoothing surfaces of the divided pieces of the non-erodedportion and the divided pieces of the new quartz glass material by aflame treatment prior to forming parts by welding.
 9. A method ofrefurbishing a quartz glass component in an eroded or contaminated anddeteriorated state, comprising: inspecting an eroded or contaminated anddeteriorated quartz glass component by irradiating same with ultravioletlight of a wavelength of 200-380 nm to cause a fluorescence effect;determining an erosion or contamination status through visual inspectionof differences in fluorescing colors visible upon irradiation of theeroded or contaminated and deteriorated quartz glass component, thecolors being attributable to surface deposit on the eroded orcontaminated and deteriorated quartz glass component and to the quartzglass of the eroded or contaminated and deteriorated quartz glasscomponent; performing a predetermined cleaning method on the eroded orcontaminated and deteriorated quartz glass component, the predeterminedcleaning method comprising a primary cleaning method followed by asecondary cleaning method, the primary cleaning method being a dry iceblast cleaning comprising peeling off the surface deposit by sprayingdry ice particles onto the eroded or contaminated and deterioratedquartz glass component together with compressed air or compressednitrogen gas and utilizing thermal contraction to effect removal of thesurface deposit, the secondary cleaning method being a high temperatureheat cleaning comprising sublimating or incinerating the surface depositby placing the eroded or contaminated and deteriorated quartz glasscomponent in a high-temperature furnace and heating the quartz glasscomponent to a temperature in a range of about 700° C. to a maximumtemperature of 1050° C., the range being sufficient to remove thesurface deposit and the range being below a strain point of quartzglass; whereby, after performing the predetermined cleaning method, acleaned quartz glass component is obtained; checking the erosion orcontamination status of the cleaned quartz glass component byirradiating the cleaned quartz glass component with ultraviolet lightand visually inspecting the cleaned quartz glass component; andperforming a post-cleaning treatment selected from a removal andreplacement treatment in which a portion of the cleaned quartz glasscomponent is removed and replaced with a replacement portion of newquartz glass material and a flame treatment without the removal andreplacement treatment.
 10. The method of claim 9, wherein thepost-cleaning treatment is a flame treatment comprising the steps offlame treating the cleaned quartz glass component, whereby the cleanedquartz glass component is refurbished.
 11. The method according to claim9, wherein the post-cleaning treatment is a flame treatment comprisingthe steps of: carrying out a flame treatment on an eroded portion of thecleaned quartz glass component without separating the eroded portionfrom the non-eroded portion of the cleaned quartz glass component,whereby the eroded portion is thickened and refurbished by using amaterial that is the same as the material of the eroded portion.
 12. Themethod of claim 9 wherein the post-cleaning treatment is a removal andreplacement treatment comprising the steps of separating the cleanedquartz glass component into an eroded portion and a non-eroded portion,discarding the eroded portion, substituting the eroded portion with areplacement portion of new quartz glass material, dividing thenon-eroded portion separated from the quartz glass component intodivided pieces of the non-eroded portion, dividing the new quartz glassmaterial into divided pieces of the new quartz glass material, formingparts by welding the divided pieces of the non-eroded portion and thedivided pieces of the new quartz glass material, and welding the partsto form an integral structure.
 13. The method according to claim 9,wherein the post-cleaning treatment is a removal and replacementtreatment comprising the steps of providing a number of replacementportions of new quartz glass material that are equal to a number ofdivided pieces of the non-eroded portion and pairing the portions of newquartz glass material and divided non-eroded portions, whereby pairs areformed; welding surfaces of the pairs to form parts: and welding theparts to form an integral structure for refurbishment.
 14. The methodaccording to claim 13, wherein the new quartz glass material includesnew quartz glass material remaining after manufacturing other quartzglass components from new quartz glass material.
 15. The methodaccording to claim 14, wherein the new quartz glass material has a ringshape, discoid shape, or polygonal shape, or has a shape dividedtherefrom.
 16. The method according to claim 13, wherein the new quartzglass material has a ring shape, discoid shape, or polygonal shape, orhas a shape divided therefrom.
 17. The method of claim 13 furthercomprising the step of smoothing surfaces of the divided pieces of thenon-eroded portion and the divided pieces of the new quartz glassmaterial by a flame treatment prior to forming parts by welding.
 18. Themethod according to claim 9, wherein the post-cleaning treatment is aflame treatment comprising the steps of: dividing the cleaned quartzglass component into pieces having an eroded portion and a non-erodedportion; carrying out a flame treatment on the eroded portion of thequartz glass component, whereby the eroded portion is thickened by usingthe same material as the material of the eroded portion; and weldingsurfaces of the pieces together to form an integral structure.
 19. Themethod according to claim 9, wherein the eroded or contaminated anddeteriorated quartz glass component is a chamber part for use in aplasma treatment apparatus for fabricating a semiconductor orliquid-crystal device.
 20. The method according to claim 9, wherein thequartz glass component is step-, ring-, or disc-shaped.